What does prediabetes actually mean?
Prediabetes is a term used to describe blood sugar levels that are higher than normal, but haven't yet reached the point where a diagnosis of type 2 diabetes is made. Think of it as a signal, your body is telling you that the way it handles glucose is under strain.
Glucose (sugar) is your body's primary fuel source. After you eat, your digestive system breaks food down into glucose, which enters your bloodstream. The hormone insulin, made by your pancreas, acts like a key, letting glucose move from your blood into your cells where it can be used for energy.
In prediabetes, two things are typically happening at once, and understanding both helps explain why it progresses the way it does.
The first is insulin resistance. Your cells, particularly in your muscles, liver, and fat tissue, stop responding to insulin as efficiently as they should. The key is still there, but the lock isn't working as well. Your pancreas compensates by producing more insulin to try to push glucose into cells and keep blood sugar stable. For a while, it manages.
The second is beta cell dysfunction. The beta cells in your pancreas are the ones that make insulin. Under the sustained pressure of producing extra insulin to overcome resistance, they gradually begin to tire. Their ability to secrete insulin, particularly that important first burst after a meal, starts to decline. This is the part that's often underappreciated: prediabetes isn't just about cells ignoring insulin, it's also about the pancreas slowly losing its ability to keep up. Research shows these two processes, insulin resistance and beta cell decline, happen simultaneously, not one after the other.
The result is blood sugar that sits higher than it should, for longer than it should, after meals and overnight. Over time, without change, that persistent elevation causes the gradual damage we associate with type 2 diabetes.
Worth knowing
Prediabetes often has no symptoms at all. Most people who have it feel completely well. That's why routine blood tests, not waiting for something to feel wrong, are how it tends to be found.
How is it diagnosed?
In Australia, prediabetes is identified through blood tests, most commonly an HbA1c (which reflects your average blood sugar over the past two to three months) or a fasting blood glucose test. Sometimes both are used together to get a clearer picture.
The table below shows the ranges your GP uses. These are the thresholds used in Australian general practice, the exact terminology can vary slightly between different guidelines, but the clinical picture is consistent.
| Test | Normal | Prediabetes range | Diabetes |
|---|---|---|---|
| HbA1c | Below 5.7% (Below 39 mmol/mol) |
5.7–6.4% (39–47 mmol/mol) |
6.5% or above (48 mmol/mol or above) |
| Fasting blood glucose | Below 5.5 mmol/L | 5.5–6.9 mmol/L | 7.0 mmol/L or above |
Source: RACGP Management of Type 2 Diabetes: A Handbook for General Practice (2024 edition).
It's also worth knowing that a single borderline result doesn't automatically lead to a diagnosis. Your GP will look at the full picture, your result, your risk factors, how you've been feeling, before deciding what it means for you specifically.
Who is at risk?
Prediabetes is more common than many people realise. Several factors can increase your likelihood of having it, including:
Family history plays a significant role, if a parent or sibling has type 2 diabetes, your own risk is higher. Body weight and where fat is stored matters too, particularly fat carried around the abdomen. Physical inactivity, sleep quality, and stress all affect how your body handles insulin. So does age, risk increases from around 45 onwards, though younger people are increasingly affected.
In women, a history of gestational diabetes (diabetes during pregnancy) is a significant risk factor worth discussing with your GP. Certain ethnicities, including South Asian, East Asian, Middle Eastern, Pacific Islander, and Aboriginal and Torres Strait Islander backgrounds, also carry higher risk at lower body weight thresholds.
None of these are reasons to feel alarmed. They're simply useful information that helps your GP understand your individual situation and tailor any recommendations accordingly.
Can prediabetes be reversed?
For many people, yes. This is one of the most important things I want patients to take away from this.
The evidence from Australian and international research consistently shows that lifestyle changes can significantly reduce the risk of prediabetes progressing to type 2 diabetes. The two areas that make the biggest difference are movement and eating patterns, and neither needs to look extreme to be effective.
Modest, sustainable changes tend to outperform drastic short-term ones. Aiming for around 150 minutes of moderate activity per week, broken up however suits your life, and moving toward a diet that reduces processed carbohydrates and ultra-processed foods, while keeping plenty of vegetables, protein, and whole grains, is a genuinely powerful starting point.
Sleep and stress are less talked about but equally real. Consistently poor sleep affects insulin sensitivity directly. Chronic stress elevates cortisol, which drives blood sugar up. These aren't lifestyle factors to feel guilty about, they're things worth addressing as part of a whole-person approach.
The window that matters
Prediabetes is often described as a warning sign, but I prefer to think of it as a useful piece of information that arrives before the more serious problem. That window, where change can genuinely shift the trajectory, is the one worth using.
What happens at a GP appointment?
If your blood test has come back showing prediabetes, a longer appointment with your GP gives you the space to actually understand what your result means for you, not just the number, but the context around it.
That conversation typically covers your current lifestyle, other relevant risk factors, and what realistic changes might look like given your life circumstances. It's not about being lectured, it's about building a picture together and finding a plan that actually fits.
Depending on your situation, your GP may suggest referral to a dietitian or diabetes educator, regular monitoring of your HbA1c (usually annually), and checking related markers like blood pressure and cholesterol, which often travel alongside blood sugar issues.
For most people with prediabetes, medication isn't the starting point. Lifestyle is. And the evidence strongly supports leading with that.
Clinical information in this article is based on the RACGP Management of Type 2 Diabetes: A Handbook for General Practice (2024 edition) and the Australian Diabetes Society/ADEA/Diabetes Australia Position Statement on Screening and Management of Prediabetes in Adults in Primary Care (2020). This is general information only, your GP can advise on what's relevant for your individual situation.
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